main tab issue

After clicking on the record link in a record list, we redirect the user to a specific (cloned) page because in our application we use several different pages for the same object type (using onload event and window.location). Every page has their own main tab in the application. Unfortunately,when we redirect the user to the right page, the application jumps to another main tab which is not the tab which belong to the page we have configured. So the right page is shown but the wrong main tab is displayed. This is strange behaviour because we have configured the page in a specific main tab. Can we get the focus on a specific main tab in this situation? Or is this a bug? Additional info: clicking on a main tab result in displaying the right page. But the other way around, jumping to a page with window.location javascript doesn't show the right main tab.